Electric heating device for installing solder sleeves by radiant heat



Feb. 11, 1969 R. s FOREMAN ETAL 3,427,433

ELECTRIC HEATING DEVICE FOR INSTALLING SOLDEH SLEEVES BY RADIANT HEAT Sheet Filed Oct. 12. 1965 RALPH .S. FORE/W19 Fob 19L D E. 5W/TZER KENNETHJI JP/LLE'I? DUIYHLD A. flLLfl/Y INVENTORS AUTQQ/VEVS.

Feb. 11. 1969 R. s. FOREMAN ET AL ELECTRIC HEATINGv DEVICE FOR INSTALLING SOLDER SLEEVES BY RADIANT HEAT Sheet L of 3 Filed 001:. 12, 1965 6 fiaz:

BY fi g s R. s. FOREMAN ETAL 3,427,433 ELECTRIC HEATING DEVICE FOR INSTALLING SOLDER Feb. 1 1, 1969 sLEEvEs BY RADIANT HEAT SheeE 3 of 5 Filed Oct. 12, 1965 Rox /up 5. s w/ TZEK Ai/WVETHIJP/A 1 7? DODWZD 1?. 9.4 L 0N M n w m 5 m INVENTORS AZZWAEYS.

United States Patent 3,427,433 ELECTRIC HEATING DEVICE FOR INSTALLING SOLDER SLEEVES BY RADIANT HEAT Ralph S. Foreman, Los Altos, Ronald E. Switzer and Kenneth J. Spiller, Mountain View, and Donald R. Allan, Menlo Park, Calif., assignors to Raychem Corporation, Redwood City, Calif., a corporation of California Filed Oct. 12, 1965, Ser. No. 495,125 US. Cl. 219-347 12 Claims Int. Cl. Hb 1/02, 3/02 ABSTRACT OF THE DISCLOSURE A heating device for installing solder sleeves by radiant heat includes an ellipsoidal reflector having a pivotally openable end to provide access to a Work holder at one of the focal points. An electric lamp is positioned at the other focal point. The control circuit for the lamp includes a first normally open switch for energizing the lamp, a second normally closed switch which is opened by the opening of the reflector end to prevent energization of the lamp when the end is open to expose the lamp and an automatic timer that is preset to determine the length of time the lamp is energized.

This invention relates to a heating device and more particularly relates to an infrared heating device for use with heat recoverable sleeves having fusible inserts therein.

In Wetmore application, Ser. No. 211,747, filed July 23, 1962, now patent No. 3,243,211 several types of novel electrical connectors are disclosed. The electrical connectors of the Wetmore application, the disclosure of which is incorporated by reference herein, include a dimensionally heat unstable member such as a sleeve in which is placed a solder insert. In a typical connector of this type, both ends of the members or sleeve are open to receive the electrical conductors that are to be connected. Upon heating, the member or sleeve is caused to shrink and firmly grip the electrical connectors while the solder is caused to flow and form a soldered connection between the two electrical conductors. The sleeve acts to contain the movement of the solder so that a good soldered joint is assured.

In general such members or sleeves are made of a material having the property of plastic or elastic memory and are expanded under heat and pressure to a diameter greater than their normal diameter and cooled while kept under pressure. A sleeve treated in this manner will retain its expanded position until it is again heated to above its heat recovery temperature at which time it will recover to its original shape. Examples of materials useful in forming such dimensionally heat unstable recoverable members may be found in Currie Patent No. 2,027,962 and Cook et al. Patent No. 3,086,242, the disclosures of which are incorporated herein by reference. Polymeric materials which have been crosslinked by chemical means or by irradiation, for example, with high energy electrons or nuclear radiation, such as those disclosed in the Cook et a1. patent are preferred for use in the present invention. Non-crystalline polymeric materials exhibiting the property of plastic or elastic memory, such as polyurethane, ionomers, etc. could also be used in practicing the present invention. The device of the present invention is equally useful for sleeves made from material having either plastic or elastic memory; consequently, as used herein, the term elastic memory and plastic memory are used interchangeably and are intended to be mutually inclusive.

In installing connectors of this type, which for convenience will hereinafter be referred to as solder sleeves,

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heat is usually applied by the use of a combination of convection and conduction heating. A hot air blower is brought into the vicinity of the sleeve to be installed and a stream of hot air is directed onto the sleeve. While this method provides satisfactory soldered joints, it has several disadvantages. The surface of the typical heat recoverable sleeve cannot be heated above approximately 600 F. without damage occurring. The solder insert acts as a large heat sink and requires that a significant amount of energy be transferred to its before it melts. However, the plastic of the sleeve is a poor thermal conductor and hence the time required for the melting of the solder cannot be decreased beyond a relatively long period, typically on the order of 10 to 20 seconds. This long heating cycle caused high production costs and, in some cases, results in scorching of the sleeve. In addition, to form the best quality soldered joints, it is desirable to heat the metals to be soldered to a temperature equal to or above the melting temperature of the solder prior to the solder melting. It is thus desirable to heat the wires or electrical conductors to be joined as well as the solder itself. The hot air method does not achieve this to the desired extent. Shorter heating cycles and better internal heating of the wires have been achieved by supplementing the hot air heating with induction heating but the equipment required is complex, costly, and requires precise control.

In a US. patent application Ser. No. 495,119 filed Oct. 12, 196 5, by Hugh Paul Sherlock entitled, Method of Recovering Heat Recoverable Articles, and assigned to the assignee of the present invention, there is disclosed and claimed an improved method of installing such heat recoverable sleeves. Briefly, the method of that application, the disclosure of which is incorporated by reference herein, utilizes radiant energy to raise the temperature of the sleeve to its recovery temperature and simultaneously to raise the temperature of a fusible insert to its melting temperature. In this manner, the sleeve can be made to recover just before the insert flows with the result that the sleeve will control the flow of the insert. The material from which the sleeve and insert are fabricated, or their spatial relationship, can be made such that the substrate or object on which the sleeve is to be installed can also be heated by the radiant energy. This is desirable, for example, when a solder joint is to be made.

It is an object of the present invention to provide improved apparatus for installing heat recoverable sleeves having fusible inserts.

It is another object of the present invention to provide apparatus for simultaneously applying heat energy to a heat recoverable sleeve and to a fusible insert positioned therein.

It is a further object of the invention to provide a heating device which is simple to operate and which greatly reduces the time required to install a recoverable sleeve having a fusible insert.

It is necessary that any method or device used in installing solder sleeves or the like be convenient to use, safe, and relatively foolproof. According to the present invention, a heating device or tool is provided which utilizes the principle of radiant heating, which is portable, and which is provided with safety features which prevent either the operator or the sleeve itself from being damaged. Basically, the device comprises a closed reflector, preferably ellipsoidal in configuration, having a suitable source of heat energy positioned at one of the focal points. The other end of the reflector is provided with removable portion so that access to the other focal point is possible. Means are provided for holding the solder sleeve to be installed at the second focal point. An electrical circuit is provided for energizing the energy source, and a safety switch is incorporated in the electrical circuit to prevent the source from being actuated while the chamber is open. The electrical circuit is also provided with an automatic timer that is preset to determine the length of time that the source is actuated. This time can be preset to any desired value depending upon the particular material to be soldered and the solder sleeve used. It can thus be seen that the most unskilled operator can effectively utilize this tool to rapidly make installations of solder sleeves without risk of danger to himself or to the sleeves.

These and other objects and advantages of the present invention will become more apparent upon reference to the accompanying description and drawings in which:

FIGURE 1 is a side elevation of the heating device of the present invention;

FIGURE 2 is a cross-sectional view of the heating device of FIGURE 1;

FIGURE 3 is a partial cross-sectional view showing the heating device of FIGURE 2 in its opened position;

FIGURE 4 is a cross-sectional view taken along lines 44 of FIGURE 2; and

FIGURE 5 is a front elevation of the device of FIG- U-RE 1 with the tip portion and solder sleeve removed.

Turning now to the drawings, the details of the heating tool of the present invention are illustrated. As shown in FIGURE 1, the reflector is mounted on a frame 11 having a handle or pistol grip 12. An end or tip portion 13 of the reflector 10 is unconnected to the remainder of the reflector and is mounted on an arm 14 which can be moved to move the tip 13 away from the remainder of the reflector 10 by depressing a trigger 15. The forward end of the reflector 10 is provided with a work holding mechanism, generally indicated at 16, which is accessible when the tip 13 is moved away from the remainder of the reflector. A push button 17 is provided on the side of the frame 11 at the upper end of the handle 12 for actuating the energy source positioned within the reflector 10. A cable 18 connects the heating device to a source of power and a suitable timer. A solder sleeve 19 is shown in position in the work holding mechanism 16.

The details of the heating device shown in FIGURE 1 are illustrated more clearly in FIGURES 2 through 5. The reflector 10 is made up of two sections 20 and 21 which, together with the tip section 13, make up a closed chamber 22. The reflector is ellipsoidal in configuration and has a lamp 23 positioned at one focal point and the work holding mechanism 16 positioned in the vicinity of the other focal point. The rays from the lamp 23 are focused by the surface of the reflector at the forward focal point and thus substantially all of the radiant energy emitted by the element of the lamp 23 at the rear focal point is brought to bear on the solder sleeve 19 positioned by the work holding mechanism 16 at the forward focal point. For good reflectivity, the inner surface of the reflector 10 is preferably highly polished gold plating. The lamp 23 may be any suitable lamp, for example, a Sylvania 500 watt iodine quartz lamp, model 500 Q/ CL. This lamp is preferably operated at approximately 110 volts. Its wave length distribution is such that over 95% of its energy is from 0.4 to 4.2 microns with a peak of about 0.97 micron. The reflector sections 20 and 21 are telescoped to form a good reflective surface and are attached to the frame 11 by means of a tab 24 and a pin 25. It should be understood that while an ellipsoidal reflector is shown, other shapes could also be used. For example, the reflector could be made to have a generally oval cross-section so that the heating zone would be elongated.

The tip portion 13 of the reflector 10 is welded or otherwise fastened to one end of the U-shaped arm 14, the other end of the arm 14 being pivoted about a pin 26. An adjustable actuating rod 27 has one end connected to the arm 14 and the other end connected to the trigger 15. The trigger 15 is pivotally mounted about a pin 28. A housing 29 is mounted with two screws within the frame 11. A spring 30 is provided for urging the trigger 15 in the forward direction so that the rod 27 normally causes the arm 14 to keep the tip portion '13 in engagement with the remainder of the reflector 10. As shown in FIGURE 3, when the trigger 15 is depressed, or pulled back towards the handle 12, the rod 27 pivots the arm 14 about the pin 26 with the result that the tip portion 13 is moved away from the remainder of the reflector 10 exposing the work holding mechanism 16.

The rod 27 is provided with a block 31 so that when the trigger 15 is depressed the block 31 is moved until it engages a shoulder 32 on a generally U-shaped bar 33. The forward ends of the bar 33 are mounted by a pin 34 to a lever 35 which is pivotally mounted on a pin 36. When the trigger 15 is further depressed, the bar 33 is moved and causes the lever 35 to pivot about the pin 36. The first portion of the travel of the rod 27 causes the arm 14 to be pivoted around pin 26 so that the tip portion 13 is moved a short distance away from the remainder of the reflector exposing the work holding mechanism 16. The second portion of the travel of the rod 27 causes the work holding mechanism 16 to release the solder sleeve 19.

A spring 37 is mounted on a pin 38 on the member 33 and on a pin 39 on a block 40 and is provided for urging lever 35 in the counterclockwise direction when trigger 15 is released. The result is that the mechanism 16 closes on cables 41 and 42 and holds them in position before the tip portion 13 is completely closed. This provides a visual check on the position of solder sleeve 19 and cables 41 and 42 in relation to each other and in relation to the focal point of the closed chamber 22 prior to the closing of the tip portion 13.

The work holding mechanism 16 includes a member 43 mounted on the lever 35 and extending through a slot 44 formed in the front of block 40. A tube 45 is slip fit on the member 43 and has attached thereto a horizontal mounting rod 46. A pair of heavy wires 47 and 48, formed to cradle the cables 41 and 42, are attached to the rod 46. Another pair of loops or cradles for the cables 41 and 42 are formed by pairs of stiff wires 49 and 50 which are attached to a horizontal mounting rod 51 which is held by two rods 52 which extend through a slot 53 in section 20 of the reflector 10, then bend around the reflector section 20. The ends of the rods 52 are inserted into two holes in the block 40. When the lever 35 is pivoted by backward movement of member 33, the wires 47 and 48 are moved away from the wires 49 and 50 releasing the solder sleeve 19 and cables 41 and 42.

As can best be seen in FIGURE 4, the tip portion 13 is provided with apertures 54 and 55 through which the electrical conductors, such as cables 41 and 42, or other objects to be connected, may pass. The ends of the cables 41 and 42 are positioned within a solder insert 56 of the solder sleeve 19.

The lamp 23 is mounted in a socket 57 positioned in the handle 12 adjacent the housing 29. In order to receive the lamp 23, section 21 of the reflector 10 is provided with a pair of aligned apertures 58 and 59. The upper portion of the lamp 23, that is, the portion beyond the reflector section 21, extends into a cavity 60 formed in a cap 61. The cap 61 is mounted in any suitable fashion to the handle 12, for example by means of a screw 62. Preferably, the cavity 60 is lined with a ceramic insulating material 63. The portion of the lamp 23 which extends below the reflector section 21 is also preferably surrounded by ceramic insulating material 64. When the lamp 23 needs to be replaced, all that is required is that the cap 61 be removed and the lamp unscrewed from the socket 57 and replaced. The cap 61 is then replaced and the device is again ready for use.

The housing 29 has mounted therein a pair of microswitches 65 and 66. The micro-switch 65 is normally closed and is opened when the trigger 15 is depressed. This breaks the power circuit to the lamp 23 and insures that the lamp cannot be energized when the tip portion 13 is displaced from the remainder of the reflector 10. The micro-switch 66 is normally open and is closed by pushing the push button 17. When the push button 17 is depressed, and the trigger 15 is in the normal position, the circuit to the lamp 23 is completed and the lamp is illuminated. The circuit is provided with a third switch located in the timer which opens the circuit after the passage of a predetermined time interval. As pointed out above, this interval can be set in accordance with the characteristics of the solder sleeve being installed, for example, the composition of the material of the sleeve and the mass of the solder insert. If desired, the timer may be located in the handle 12 or elsewhere in the frame 11 to eliminate the need for an external timer and permit the heating device to be simply plugged into any conventional electrical outlet.

As a typical example of the operation of this invention, a sleeve of the type used in a Type Dl44-0l solder sleeve sold by Rayclad Tubes, Inc., of Redwood City, Calif, having an axial length of /3 inch, and inside diameter of 0.20 inch and a wall thickness of 0.010 inch was provided with a solder insert of the following composition: tin 63%, lead 37%; and having a mass of 0.1 gram. Using the apparatus described above, it took 0.75 second for the sleeve to be heated to its recovery temperature of 347 F. and approximately 0.5 further seconds for the solder insert to melt and flow. When a solder sleeve is actually installed, the irradiation must be continued until proper solder wetting of the conductors or other substrate is achieved.

From the foregoing description, it can be seen that apparatus has been developed for providing suflicient energy to a heat recoverable sleeve to cause it to recover while simultaneously providing sufficient energy to a solder insert positioned within the sleeve to cause it to reach its melting temperature just after the sleeve begins to recover. Energy can also be provided to the substrate in this manner so that a good solder joint is obtained. It should be understood that while the invention has been described in terms of a sleeve having a solder insert, it is equally useful in connection with a sleeve having any type of fusible insert. If the insert is solder, the sleeving material must exhibit elastomeric properties at at least its recovery temperature. It should also be understood that the apparatus provided is also useful for shrinking other heat shrinkable members, whether or not they are provided with fusible inserts. In the foregoing description and in all the following claims, it has been assumed that all the energy not absorbed by the sleeve is transmitted to the insert or to the substrate or object on which it is installed. While this is not exactly true because of a small amount of reflection from the surface of the sleeve and some internal scattering, the assumption is substantially true and for all practical purposes accurate as the amount of reflected energy is quite small.

The invention may be embodied in other specific forms not departing from the spirit or central characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed is:

1. A heating device comprising: a reflector forming a closed chamber, one end portion of said reflector being movable away from the remainder of said reflector to provide access to a focal point thereof; frame means for mounting said reflector; pivotal means pivotally mounted on said frame means, one end of said pivotal means being attached to said end portion, pivotal movement of said pivotal means causing movement of said end portion away from said remainder of said reflector; mechanically actuable means on said frame means; means coupling said mechanically actuable means to said pivotal means whereby said mechanically actuable means is actuable to pivot said pivotal means; means positioned within said reflector for locating a workpiece at said focal point; a lamp positioned within said reflector; and electrical circuit means for supplying electrical energy to said lamp; said circuit means including first normally open switch means and second normally closed switch means, said second switch means being engageable by and operable in response to actuation of said mechanically actuable means for opening said circuit means; and means for closing said first switch.

2. A heating device comprising: a reflector forming a closed chamber, one end portion of said reflector being movable away from the remainder of said reflector; frame means for mounting said reflector, said frame means including a handle; pivotal means pivotally mounted on said frame means, one end of said pivotal means being attached to said end portion, pivotal movement of said pivotal means causing movement of said end portion away from said remainder of said reflector; trigger means mounted on said frame means, means coupling said trigger means to said pivotal means whereby said trigger means is operable to pivot said pivotal means; means positioned within said reflector for locating a workpiece at one of the focal points thereof, movement of said end portion away from the remainder of said reflector permitting access to said workpiece locating means; a source of light energy positioned at the other focal point of said reflector; electrical circuit means for supplying electrical energy to light source, said circuit means including first normally open switch means and second normally closed switch means, said second switch means being engageable by and operable in response to operation of said trigger means for opening said electrical circuit means; and means for closing said first switch means.

3. The device of claim 2 wherein said electrical circuit means further includes timing means operable to open said electrical circuit means a predetermined time after said first switch means are closed.

4. A heating device comprising: a generally ellipsoidal reflector forming a closed chamber, one end portion of said reflector being movable away from the remainder of said reflector; a frame for mounting said reflector, said frame including a handle; an arm pivotally mounted on the forward end of said frame, one end of said arm being attached to said end portion, pivotal movement of said arm causing movement of said end portion away from said remainder of said reflector; trigger means mounted on said frame adjacent said handle; means coupling said trigger means with said arm whereby said trigger means is operable to pivot said arm; cradle means positioned within said reflector for releasably locating a workpiece at approximately one of the focal points thereof, movement of said end portion away from the remainder of said reflector permitting access to said cradle means; means associated with said trigger means for opening said cradle means to release said workpiece after said movement of said end portion; a source of light energy positioned at the other focal point of said reflector; electrical circuit means for supplying electrical energy to said light source, said circuit means including first normally open switch means, second normally closed switch means engageable by and operable in response to operation of said trigger means for opening said electrical circuit means, and timing means operable to open said electrical circuit means a predetermined time after closure of said first switch means; and means for closing said first switch means.

5. A heating device comprising: a reflector forming a closed chamber, one end portion of said reflector being movable away from the remainder of said reflector to provide access to a focal point thereof, the other end of said reflector having a pair of aligned apertures formed therein; frame means for mounting said reflector, said frame means including a handle and a cap portion; means mounted on said frame means and operable for moving said end portion away from said remainder of said reflector; socket means positioned in said handle of said frame means adjacent said aligned apertures in said reflector; a lamp mounted in said socket means and extending through said apertures in said reflector; means for mounting said cap portion over the portion of said lamp extending from the one of said apertures remote from said socket; electrical circuit means for supplying electrical energy to said lamp, said circuit means including first normally open switch means and second normally closed switch means, means coupling said end portion moving means with said second switch means whereby said second switch means is operable in response to operation of said end portion moving means for opening said electrical circuit means; and means for closing said first switch means.

6. A heating device comprising: a reflector forming a closed chamber, one end portion of said reflector being unconnected to the remainder of said reflector; frame means for mounting said reflector, said frame means including a handle; an arm pivotally mounted on the forward end of said frame means, one end of said arm being attached to said end portion, pivotal movement of said arm causing movement of said end portion away from said remainder of said reflector; trigger means mounted on said frame means adjacent said handle; means coupling said trigger means with said arm whereby actuation of said trigger means causes said pivotal movement of said arm; cradle means positioned within said remainder of said reflector for receiving and locating a workpiece approximately at one of the focal points of said reflector, movement of said end portion away from the remainder of said reflector permitting access to said cradle means; means pivotally mounted on said frame for cooperating with said cradle means for firmly engaging said workpiece; means associated with said coupling means and connected to said pivotally mounted means for pivoting said pivotally mounted means away from cradle means after said end portion has been moved away from said remainder of said reflector; a source of light energy positioned within said reflector; and electrical circuit means for supplying power to said source.

7. The device of claim *6 wherein said coupling means comprises a rod having a block mounted thereon, said rod being connected to said trigger means and to said arm and said associated means comprises a member through which said rod passes, movement of said rod a predetermined distance causing said block to engage said member and move said member along with said rod.

8. The device of claim 6 wherein said cradle means comprises a horizontal bar having a first plurality of wires extending therefrom and connected to said frame means and a second plurality of wires extending therefrom, said second plurality of wires being bent to receive said workpiece, and wherein said pivotally mounted means comprises a horizontal bar having a series of wires extending therefrom, said wires being bent to hold said workpiece against said second plurality of wires.

9. The device of claim 6 wherein said electric circuit means include first normally open switch means, second normally closed switch means engageable by and operable in response to operation of said trigger means for opening said electrical circuit means; timing means operable to open said electrical circuit means a predetermined time after closure of said first switch means; and means for closing said first switch means.

10. A heating device for installing a solder sleeve on a pair of electrical conductors comprising: a generally ellipsoidal reflector forming a closed chamber, one end portion of said reflector being unconnected to the remainder of said reflector to provide access to a focal point thereof, the other end of said reflector having a pair of aligned apertures formed therein to provide access to the other focal point of said reflector; frame means for mounting said reflector, said frame means including a handle and a cap portion; an arm pivotally mounted on the forward end of said frame means, one end of said arm being attached to said end portion, pivotal movement of said arm causing movement of said end portion away from said remainder of said reflector; trigger means mounted on said frame means adjacent said handle; means coupling said trigger means with said arm whereby actuation of said trigger means causes said pivotal movement of said arm; cradle means positioned within said remainder of said reflector for receiving said conductors and locating said solder sleeve approximately at said other focal point of said reflector, movement of said end portion away from the remainder of said reflector permitting access to said cradle means; means pivotally mounted on said frame means for cooperating with said cradle means for firmly engaging said conductors; means associated with said coupling means and connected to said pivotally mounted means for pivoting said pivotally mounted means away from said cradle means after said end portion has been moved away from said remainder of said reflector; socket means positioned in said handle of said frame means adjacent said aligned apertures in said reflector; a lamp mounted in said socket means and extending through said apertures in said reflector; means for mounting said cap portion over the portion of said lamp extending from the one of said apertures remote from said socket; insulating means positioned around the portions of said lamp external of said reflector; electrical circuit means for supplying electrical energy to said lamp, said circuit means including first normally open switch means, second normally closed switch means engageable by and operable in response to operation of said trigger means for opening said electrical circuit means, and timing means operable to open said electrical circuit means a predetermined time after closure of said first switch means; and push button means mounted on said frame means adjacent said handle for closing said first switch means.

11. The device of claim 10 wherein said coupling means comprises a rod having a block mounted thereon, said rod being connected to said trigger means and to said arm, and said associated means comprises a member through which said rod passes, movement of said rod a predetermined distance causing said block to engage said member and move said member along with said rod.

12. The device of claim 10 wherein said cradle means comprises a horizontal bar having a first plurality of wires extending therefrom and connected to said frame means and a second pluralitv of wires extending therefrom, said second plurality of wires being bent to receive said conductors, and wherein said pivotally mounted means comprises a horizontal bar having a series of wires extending therefrom, said wires being bent to hold said conductors against said second plurality of wires.

References Cited UNITED STATES PATENTS 7/1940 Meuer 200-6l.7 4/1959 Sisson 20061.7 

